drop if (exporter=="GER" | importer=="GER")
drop if (exporter=="BEL" | importer=="BEL")
drop if (exporter=="INO" | importer=="INO")
drop if (exporter=="VEN" | importer=="VEN")
drop if (exporter=="GUY" | importer=="GUY")
drop if (exporter=="SWE" | importer=="SWE")
drop if (exporter=="NIG" | importer=="NIG")
drop if (exporter=="TNT" | importer=="TNT")
drop if (exporter=="NEZ" | importer=="NEZ")
drop if (exporter=="FRA" | importer=="FRA")
drop if (exporter=="PAN" | importer=="PAN")
drop if (exporter=="CYP" | importer=="CYP")
drop if (exporter=="THA" | importer=="THA")
drop if (exporter=="CAN" | importer=="CAN")
drop if (exporter=="TWN" | importer=="TWN")
drop if (exporter=="HON" | importer=="HON")
drop if (exporter=="CHN" | importer=="CHN")
drop if (exporter=="UK" | importer=="UK")
drop if (exporter=="SAF" | importer=="SAF")
drop if (exporter=="PAK" | importer=="PAK")
drop if (exporter=="NOR" | importer=="NOR")
drop if (exporter=="SUD" | importer=="SUD")
